5 Mobility: An Overview

Learning Objectives

Most existing urban environments were not designed using modern accessibility principles and consequently many visually impaired and blind people experience severe difficulties in travelling even short distances in these public spaces. Although a number of blind and visually impaired people are confident and experienced travellers, significantly greater numbers of blind and deafblind people feel unable to go out without a guide. Thus, the development of travel aids, which could be used to support independent travel by blind, visually impaired and deafblind people, is an important application area for assistive technology.

Although there has been a reasonable amount of work in this area and a number of systems have been developed, many have not gone beyond the prototype stage. Of the others, some have totally disappeared and others are used by relatively small numbers of blind and visually impaired people. Therefore, there is a need for the development of reliable travel aids which have good technical performance and are also attractive to the end-user community. However, this will only be a partial solution, since the widespread adoption of fully accessible environments combined with the development of user friendly integrated assistive technology for mobility will be required to remove the barriers to mobility currently experienced by blind and visually impaired people. This chapter provides an overview of the current state of the art as an introduction to the more detailed discussion of a number of these devices and developments in subsequent chapters.

The learning objectives for this chapter include the following:

•Understanding the different types of barriers to independent mobility experienced by visually impaired and blind people.

•Understanding the approaches used by blind and visually impaired people to support (independent) mobility.

•Appreciating the range of assistive technology systems for mobility that have been developed and the general principles of several of these systems.

•Understanding the concept of a fully accessible environment and an overview of the progress made towards implementation.

168 5 Mobility: An Overview

5.1 Introduction

Much of everyday life involves the activity of moving from one place to another. Unfortunately, in many countries, facilities such as shops, leisure and sports centres are increasingly being located outside the centres of population. For visually impaired and blind people, most of whom are not able to drive, access to such locations depends on the availability of public transport and, in many cases, the assistance of a human guide. In addition, there is a tendency for people to live away from their workplace and, at least in the industrialised countries, increasing numbers of people are travelling abroad on holiday. Thus, the ability to travel at least short and medium distances and find one’s way around public spaces and commercial centres is important for personal independence, for employment and for participating in shopping and leisure activities. Consequently, visually impaired and blind people need assistive technology systems to support effective travel and to contribute to independent living and working. Further, the design of urban and other environments should be improved to make them easy to move around in and obstacles that could endanger safety, particularly of visually impaired and blind people, should be removed. This is likely to have benefits for everyone, whether visually impaired, blind or sighted.

Travelling, even for relatively simply trips, involves a number of different activities which are most easily carried out using vision. Consider a journey across a city by bus to visit a hospital consultant. The tasks involved include the following:

•Being able to avoid obstacles on the pavement.

•Walking in the right direction.

•Crossing the road safely.

•Finding the correct bus stop.

•Knowing which is the right bus.

•Paying the correct fare.

•Finding a vacant seat.

•Knowing when to get off the bus.

•Crossing the road safely (at a different location and probably using a different type of crossing).

•Walking to the hospital entrance.

•Finding the main reception desk.

•Finding and using a lift (elevator) to the correct floor.

•Locating the waiting room and the consultant’s room.

•Leaving the hospital and repeating the travel process in reverse to return home.

For such tasks, sighted and hearing people mainly rely on their sense of sight, complemented by hearing. Visually impaired and blind people are only able to use their sense of sight to a limited extent or possibly not at all and, except in the case of deafblind people, will be largely reliant on hearing. Both blind and deafblind